Effects of nitriding on the microstructure and properties of VAlTiCrMo high-entropy alloy coatings by sputtering technique

The VAlTiCrMo and (VAlTiCrMo)Nx coatings were prepared by sputtering V–Al–Ti–Cr–Mo splicing targets. The microstructure and chemical composition were analyzed by means of X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and transmission electron microscope (TEM). The high-entropy alloy coating and the corresponding nitride coating have body-centered cubic (BCC) and face-centered cubic (FCC) structures respectively. Nitriding changes the phase structure and growth mode of the high-entropy coating, and the synthesized high-entropy nitride coatings are more compact. Meanwhile, the introduction of nitrogen leads to severe lattice distortion, which improves the mechanical properties of the high-entropy coating. As the nitriding degree increases, the corrosion resistance of the high-entropy nitride coatings in 3.5 wt% NaCl solution is improved. The synthesized (VAlTiCrMo)Nx coating exhibits optimized mechanical properties and nobler corrosion resistance when the N2 flow is 800 sccm. Corrosion inhibition by the microstructures of the VAlTiCrMo and its nitride coatings. [Display omitted] •VAlTiCrMo high-entropy alloy coating and its nitride coatings prepared by splicing targets.•The change of coating structure is more obvious with the increase of nitrogen flow rate.•The introduction of nitrogen changed the structure of the coating from BCC to FCC.